Paper 2023/1239
CSI-Otter: Isogeny-based (Partially) Blind Signatures from the Class Group Action with a Twist
Abstract
In this paper, we construct the first provably-secure isogeny-based (partially) blind signature scheme.
While at a high level the scheme resembles the Schnorr blind signature, our work does not directly follow from that construction, since isogenies do not offer as rich an algebraic structure.
Specifically, our protocol does not fit into the "linear identification protocol" abstraction introduced by Hauck, Kiltz, and Loss (EUROCYRPT'19), which was used to generically construct Schnorr-like blind signatures based on modules such as classical groups and lattices.
Consequently, our scheme is provably-secure in the poly-logarithmic (in the number of security parameter) concurrent execution and does not seem susceptible to the recent efficient ROS attack exploiting the linear nature of the underlying mathematical tool.
In more detail, our blind signature exploits the "quadratic twist" of an elliptic curve in an essential way to endow isogenies with a strictly richer structure than abstract group actions (but still more restrictive than modules).
The basic scheme has public key size
Metadata
- Available format(s)
-
PDF
- Category
- Public-key cryptography
- Publication info
- A major revision of an IACR publication in CRYPTO 2023
- DOI
- https://doi.org/10.1007/978-3-031-38548-3_24
- Keywords
- Blind signatureIsogeny cryptographyPost-quantum cryptographyGroup action
- Contact author(s)
-
shuichi katsumata @ pqshield com
27182818284fu lai @ gmail com
jlegrow @ vt edu
lqin276 @ aucklanduni ac nz - History
- 2023-08-21: approved
- 2023-08-16: received
- See all versions
- Short URL
- https://ia.cr/2023/1239
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2023/1239, author = {Shuichi Katsumata and Yi-Fu Lai and Jason T. LeGrow and Ling Qin}, title = {{CSI}-Otter: Isogeny-based (Partially) Blind Signatures from the Class Group Action with a Twist}, howpublished = {Cryptology {ePrint} Archive, Paper 2023/1239}, year = {2023}, doi = {https://doi.org/10.1007/978-3-031-38548-3_24}, url = {https://eprint.iacr.org/2023/1239} }